Ink jet printers generally transport ink from an ink reservoir into a jet stack, a stack of plates that form manifolds and a pressure chamber. The ink flows through the manifolds to the pressure chamber, essentially a very small reservoir. A transducer of some sort receives an electrical signal and pushes the ink out of the pressure chamber through a nozzle to strike a printing substrate. Transporting the ink requires control over the flow rate of the ink. Dispensing the ink onto a substrate with good image quality requires that there not be any air bubbles or foreign matter in the ink that would affect the amount of ink dispensed or the integrity of the color of the ink.
Generally, controlling the flow of ink involves a weir plate. A weir plate typically controls the flow of a fluid by slowing the flow of the fluid until it reaches a bather, causing the fluid to pool up behind the plate and then eventually reach the outlet. The weir plate usually resides in the print head in a point in the flow path prior to reaching the jet stack. To remove air bubbles and foreign matter, the ink flows through a filter. The filter generally consists of two layers, one of stainless steel mesh and one of stainless steel felt.
The weir plate and the filters typically reside in the ink flow path as separate pieces. This involves attaching the two filter layers and then adding an additional weir plate after the filter. This involves three separate adhesive joints, and the additional weir plate. The added complexity to the print head increases the costs and the adhesive joints contribute possible points of failure in the printhead.